Basic windows form login in C# demo

Below is the code which accepts username and password from the user and login if successful else displays error in message box.

Here are the design view of the project:

Login Screen:

after successful login it will opens another form mentioned below:

Here is the code for the above project:

1) Program.cs:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace basic_opr_windows_app_demo1
{
    static class Program
    {
        ///

        /// The main entry point for the application.
        ///

        [STAThread]
        static void Main()
        {
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            Application.Run(new Form2());
        }
    }
}

2) Form2.cs:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace basic_opr_windows_app_demo1
{
    public partial class Form2 : Form
    {
        public Form2()
        {
            InitializeComponent();
        }

        private void label2_Click(object sender, EventArgs e)
        {

        }

        private void button1_Click(object sender, EventArgs e)
        {
            if (textBox1.Text.Trim().Equals("vin"))
            {
                if(textBox2.Text.Trim().Equals("abc"))
                {
                    MessageBox.Show("Welcome");
                    Form1 f1 = new Form1();
                    f1.Show();
                }
                else
                {
                    MessageBox.Show("Invalid username or password");
                }
            }
            else
            {
                MessageBox.Show("Invalid username or password");
            }
        }
    }
}

3) Form1.cs:

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Linq;

using System.Text;

using System.Threading.Tasks;

using System.Windows.Forms;

namespace basic_opr_windows_app_demo1

{

    public partial class Form1 : Form

    {

        public Form1()

        {

            InitializeComponent();

        }

        private void textBox2_TextChanged(object sender, EventArgs e)

        {

        }

        private void button1_Click(object sender, EventArgs e)

        {

            int a = Int32.Parse(textBox1.Text);

            int b = Int32.Parse(textBox2.Text);

            int c = a + b;

            textBox3.Text = c.ToString();

        }

        private void button2_Click(object sender, EventArgs e)

        {

            int a = Int32.Parse(textBox1.Text);

            int b = Int32.Parse(textBox2.Text);

            int c = a - b;

            textBox3.Text = c.ToString();

        }

        private void button3_Click(object sender, EventArgs e)

        {

            int a = Int32.Parse(textBox1.Text);

            int b = Int32.Parse(textBox2.Text);

            int c = a * b;

            textBox3.Text = c.ToString();

        }

        private void button4_Click(object sender, EventArgs e)

        {

            int a = Int32.Parse(textBox1.Text);

            int b = Int32.Parse(textBox2.Text);

            int c = a / b;

            textBox3.Text = c.ToString();

        }

    }

}